1. Field of the Invention
The present invention relates to a charging device for an electric automobile, which charges a storage device for supplying power to an electric motor for driving a vehicle.
2. Description of the Related Art
Electric automobiles include vehicles that employ only an electric motor as a drive source and hybrid vehicles having both an electric motor and an engine as drive sources. In both types of electric automobile, a storage device such as a battery is provided to supply power to the electric motor, and when the residual capacity of the battery decreases, the battery must be charged from the outside. In a hybrid vehicle having both an electric motor and an engine as drive sources, the battery is usually charged by driving the engine, but the battery may also be charged by supplying power from an external power source, without driving the engine.
With regard to a battery provided in a vehicle, a type of charging that is performed by an in-vehicle charger installed in the vehicle and a type of charging that is performed by a dedicated charger disposed on the exterior of the vehicle have been proposed. In the type of charging that is performed by an in-vehicle charger, a receptor to which a plug connected to an external commercial power supply is connected, or in other words a connector, is attached to the vehicle. In the type of charging that is performed by a dedicated charger disposed on the exterior of the vehicle, a receptor in which a charging gun provided on a feeder cable is connected to the charger is attached to the vehicle. To enable the battery to be charged by either the in-vehicle charger or the external dedicated charger, the vehicle is provided with both the receptor to which the power source side plug is connected, or in other words the connector, and the receptor to which the charging gun of the feeder cable is connected.
Japanese Unexamined Patent Application Publication No. 2000-4542 describes a charging device having a stationary charger that outputs rectified power by rectifying an AC 200V commercial power supply and a portable charger that outputs rectified power by rectifying an AC 100V commercial power supply, wherein a battery is charged by the portable charger, and by combining the portable charger with the stationary charger, the battery is charged using either the commercial AC 100V power supply or the commercial AC 200V power supply.
An AC 100V commercial power supply is widely distributed and can be used anywhere, which is convenient for charging, but a power supply amount thereof per unit time is limited, and therefore an AC 100V commercial power supply is not suitable for fast charging during which a large supply of power is required. To charge the battery rapidly, charging must be performed directly from a transmission line capable of supplying a large amount of power per unit time, or from an AC 200V commercial power supply or the like.
However, to respond to both normal charging using an AC 100V commercial power supply and fast charging using a higher voltage, the vehicle side must be provided with both a normal charging connection terminal and a fast charging connection terminal. This is problematic in that the connection terminal must be selected at the time of charging in accordance with the charging method, and the number of terminals exposed to the exterior of the vehicle increases.
In an electric automobile, meanwhile, when the charging capacity of the battery decreases such that the battery goes flat, travel becomes impossible, and therefore it has been proposed that the vehicle having the flat battery be charged using a dedicated charging vehicle. However, this is not convenient since time is wasted waiting for the dedicated charging vehicle to arrive. Convenience is improved when the vehicle having the flat battery can be charged by an electric automobile traveling in the vicinity, but to make this possible, a new feeding connection terminal for establishing a cable connection with another vehicle must be provided on the vehicle and exposed to the vehicle exterior, leading to an undesirable further increase in the number of terminals.